switch to bundled http proxy connector

go.mod

@@ -3,8 +3,7 @@ module github.com/Snawoot/dumbproxy
 go 1.13
 
 require (
-	github.com/magisterquis/connectproxy v0.0.0-20200725203833-3582e84f0c9b // indirect
 	github.com/tg123/go-htpasswd v1.2.0
 	golang.org/x/crypto v0.0.0-20220829220503-c86fa9a7ed90
-	golang.org/x/net v0.5.0 // indirect
+	golang.org/x/net v0.5.0
 )

go.sum

@@ -2,8 +2,6 @@ github.com/GehirnInc/crypt v0.0.0-20200316065508-bb7000b8a962 h1:KeNholpO2xKjgaa
 github.com/GehirnInc/crypt v0.0.0-20200316065508-bb7000b8a962/go.mod h1:kC29dT1vFpj7py2OvG1khBdQpo3kInWP+6QipLbdngo=
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/magisterquis/connectproxy v0.0.0-20200725203833-3582e84f0c9b h1:xZ59n7Frzh8CwyfAapUZLSg+gXH5m63YEaFCMpDHhpI=
-github.com/magisterquis/connectproxy v0.0.0-20200725203833-3582e84f0c9b/go.mod h1:uDd4sYVYsqcxAB8j+Q7uhL6IJCs/r1kxib1HV4bgOMg=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=

upstream.go

@@ -0,0 +1,166 @@
+package main
+
+import (
+	"bufio"
+	"bytes"
+	"context"
+	"crypto/tls"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"net/url"
+	"strings"
+	"sync"
+
+	xproxy "golang.org/x/net/proxy"
+)
+
+type HTTPProxyDialer struct {
+	address  string
+	tls      bool
+	userinfo *url.Userinfo
+	next     ContextDialer
+}
+
+func NewHTTPProxyDialer(address string, tls bool, userinfo *url.Userinfo, next Dialer) *HTTPProxyDialer {
+	return &HTTPProxyDialer{
+		address:  address,
+		tls:      tls,
+		next:     maybeWrapWithContextDialer(next),
+		userinfo: userinfo,
+	}
+}
+
+func HTTPProxyDialerFromURL(u *url.URL, next xproxy.Dialer) (xproxy.Dialer, error) {
+	host := u.Hostname()
+	port := u.Port()
+	tls := false
+
+	switch strings.ToLower(u.Scheme) {
+	case "http":
+		if port == "" {
+			port = "80"
+		}
+	case "https":
+		tls = true
+		if port == "" {
+			port = "443"
+		}
+	default:
+		return nil, errors.New("unsupported proxy type")
+	}
+
+	address := net.JoinHostPort(host, port)
+
+	return NewHTTPProxyDialer(address, tls, u.User, next), nil
+}
+
+func (d *HTTPProxyDialer) Dial(network, address string) (net.Conn, error) {
+	return d.DialContext(context.Background(), network, address)
+}
+
+func (d *HTTPProxyDialer) DialContext(ctx context.Context, network, address string) (net.Conn, error) {
+	switch network {
+	case "tcp", "tcp4", "tcp6":
+	default:
+		return nil, errors.New("only \"tcp\" network is supported")
+	}
+	conn, err := d.next.DialContext(ctx, "tcp", d.address)
+	if err != nil {
+		return nil, fmt.Errorf("proxy dialer is unable to make connection: %w", err)
+	}
+	if d.tls {
+		hostname, _, err := net.SplitHostPort(d.address)
+		if err != nil {
+			hostname = address
+		}
+		conn = tls.Client(conn, &tls.Config{
+			ServerName: hostname,
+		})
+	}
+
+	stopGuardEvent := make(chan struct{})
+	guardErr := make(chan error, 1)
+	go func() {
+		select {
+		case <-stopGuardEvent:
+			close(guardErr)
+		case <-ctx.Done():
+			conn.Close()
+			guardErr <- ctx.Err()
+		}
+	}()
+	var stopGuardOnce sync.Once
+	stopGuard := func() {
+		stopGuardOnce.Do(func() {
+			close(stopGuardEvent)
+		})
+	}
+	defer stopGuard()
+
+	var reqBuf bytes.Buffer
+	fmt.Fprintf(&reqBuf, "CONNECT %s HTTP/1.1\r\nHost: %s\r\n", address, address)
+	if d.userinfo != nil {
+		fmt.Fprintf(&reqBuf, "Proxy-Authorization: %s\r\n", basicAuthHeader(d.userinfo))
+	}
+	fmt.Fprintf(&reqBuf, "User-Agent: dumbproxy/%s\r\n\r\n", version)
+	_, err = io.Copy(conn, &reqBuf)
+	if err != nil {
+		conn.Close()
+		return nil, fmt.Errorf("unable to write proxy request for remote connection: %w", err)
+	}
+
+	resp, err := readResponse(conn)
+	if err != nil {
+		conn.Close()
+		return nil, fmt.Errorf("reading proxy response failed: %w", err)
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		conn.Close()
+		return nil, fmt.Errorf("bad status code from proxy: %d", resp.StatusCode)
+	}
+
+	stopGuard()
+	if err := <-guardErr; err != nil {
+		return nil, fmt.Errorf("context error: %w", err)
+	}
+	return conn, nil
+}
+
+var (
+	responseTerminator = []byte("\r\n\r\n")
+)
+
+func readResponse(r io.Reader) (*http.Response, error) {
+	var respBuf bytes.Buffer
+	b := make([]byte, 1)
+	for !bytes.HasSuffix(respBuf.Bytes(), responseTerminator) {
+		n, err := r.Read(b)
+		if err != nil {
+			return nil, fmt.Errorf("unable to read HTTP response: %w", err)
+		}
+		if n == 0 {
+			continue
+		}
+		_, err = respBuf.Write(b)
+		if err != nil {
+			return nil, fmt.Errorf("unable to store byte into buffer: %w", err)
+		}
+	}
+	resp, err := http.ReadResponse(bufio.NewReader(&respBuf), nil)
+	if err != nil {
+		return nil, fmt.Errorf("unable to decode proxy response: %w", err)
+	}
+	return resp, nil
+}
+
+func basicAuthHeader(userinfo *url.Userinfo) string {
+	username := userinfo.Username()
+	password, _ := userinfo.Password()
+	return "Basic " + base64.StdEncoding.EncodeToString(
+		[]byte(username+":"+password))
+}

utils.go

@@ -18,7 +18,6 @@ import (
 	"sync"
 	"time"
 
-	"github.com/magisterquis/connectproxy"
 	"golang.org/x/crypto/bcrypt"
 	"golang.org/x/crypto/ssh/terminal"
 	xproxy "golang.org/x/net/proxy"
@@ -311,8 +310,8 @@ var registerDialerTypesOnce sync.Once
 
 func proxyDialerFromURL(proxyURL string, forward Dialer) (Dialer, error) {
 	registerDialerTypesOnce.Do(func() {
-		xproxy.RegisterDialerType("http", connectproxy.New)
-		xproxy.RegisterDialerType("https", connectproxy.New)
+		xproxy.RegisterDialerType("http", HTTPProxyDialerFromURL)
+		xproxy.RegisterDialerType("https", HTTPProxyDialerFromURL)
 	})
 	parsedURL, err := url.Parse(proxyURL)
 	if err != nil {